The stratum corneum of human and animal skin is the outermost layer of the epidermis, consisting of dead cells known as corneocytes. These stratum corneum is composed of 15-20 layers of flattened cells with no nuclei and cell organelles. These layers are continually being exfoliated and replaced by new layers of dead cells. Depending on the area of the body the time for complete turnover of all layers of the stratum corneum is normally 2-4 weeks. There are many products that are designed to be applied to the surface (top layer) of the stratum corneum. These are primarily skin care and cosmetic products. Within these categories of products one benefit area that is important and has led to continual innovation is that of durability. Extending the length of time that a product remains on the skin is desirable for both cosmetic effect as well as for skin protection products like sunscreens. However, there are many drawbacks to the current approaches to creating long wearing topical products. The first is that they usually utilize adhesive polymers which impart a tight or tacky feel to the skin. Additionally they are susceptible to being dissolved by contact with water, sweat and sebum. Furthermore even the longest wearing, most durable products rarely last for more than 24 hours due to the fact that they are only attached to the top layer of the stratum corneum and once this layer is exfoliated the product or film is removed from the body along with it.
These and other deficiencies of the existing skin care treatments require improvement. The performance and consumer acceptance of skin care regimens will be greatly improved by addressing the aforementioned shortcomings.